Production of 1:5-pentanediol



Patented May 4, 1948' PRODUCTION OF 1:5-PENTANEDIOL John George MackayBremner and Frederick Starkey, Norton-on-Tees, England, essirnors toImperial Chemical Industries Limited, a corporation of Great Britain NoDrawing. Application June 5, rate. Serial No. crease. Great Britain Mayas, 1945 l invention relates to the production of 1,5- penol.

According to the present invention there is provided a process for theproduction of 1.5- pentanediol which comprises reacting 2,3-dlhydropiiiin the liquid phase with water and hyen at elevated perature andpressure in the presence oi a hydrogenating catalyst.

sures of at least 30 atmospheres gauge and tmperatures of at least 150C. may be em-- ployed. Howevenpressures of at least 50 atmospheres gaugeand temperatures in excess of 200 G. are desirable. The preferredreaction conditions are 250-275" C. and a pressure oi at least atmheresgauge, e. p. 230-250 atmospheres gauge. It is undesirable to employtemperatures much above 400 C. Hie stoichiometric proportion oi waterrelative to 2,3-dlhydropyran may be employed, but it is preferred toemploy a proportion greater than this for example up to about 4 ts thatof the 2,3-dihydropyran by weight. .Jti process may be operatedbatchwise or continuously.

The preferred hydrogenating catalysts are the teller: copper containingcatalysts, for n; pie copper chromite such as copper barium chr0- mitc.and copper potassium chromite, foramlnate copper aluminium, alloyskeletal copper known as Raney copper. and fused copper catalyst insubstantially metallic form, prepared by reducing fused copper oxide.Under the preferred reaction conditions as specified above all of these.give yields of over 00%, and some e. a. foraminate copper n A. andcopper barium chromite give as much as 00%. Other catalysts suitable foruse in the process but which are not, however, so edective comprisenickel on kieselguhr (30% nickel for example), nickel chromite, alumihichromite Al) copper supported on described in co-pendlng applicationSerial No.

106,809, filed October 30, 1946. The copper chromite catalysts with orwithout the addition of barium orpotassimn may be prepared for exampieas described in Organic Syntheses, Collective Volume H (1943), pages142-145. The aluminium chromite catalysts may be prepared in the mannerdescribed in British specification Nos. 570,551 and 570.556. I

A nickel chromite catalyst may be prepared for example by addingammonia, liquor to a solution of nickel nitrate and chromium trioxidewarmed to 0., in which the concentration or each is one filth. molar,until no further precipitate is formed. The precipitate is filtered 0dand dried at C. The dry cake is carefully decomposed at 350 C. and thencalcined at 350 0. for 3 hours. The product, which has the compositionis pelleted and is activated by reduction with hydrogen at about 400 C.

The nickel-on-k-ieselguhr catalyst is prepared for example by addingkieselguhr to a l-molar solution of nickel nitrate in such proportionthat the fully reduced catalyst as described hereunder contains about37% nickel as metal. To the mixture at 60 C. there is added a 20%solution of sodium carbonate in an amount corresponding to one and onehalf times that required theoretlcally to precipitate nickel carbonate.The

slurry is filtered, washed until its sodium content is not more than0.1%, and is then dried. The catalyst is activated by reducing withhydrogen at about 400 C.

A beryllium chromite catalyst is prepared for example by adding ammoniato a solution at room temperature containing beryllium nitrate andammonium dichromate, in molar and half-molar concentrationsrespectively, until precipitation is complete. The precipitate isfiltered and dried at 120 (3., and the dry product is decomposed at 300C. and finally ignited at 500 6. for 2 hours. The catalyst is activatedby reduction with hydrogen at about 300 C.

A silver chromite catalyst is prepared for example by adding ammonialiquor to a solution of silver and chromium nitrates in which theconcentration of each is twice molar until precipitation is complete.The paste is dried at 120 (3., decomposed and finally calcined at 300 C.for 4 hours. The catalyst is activated by reduction with hydrogen at 300C. for about 1 hour.

A copper on kieselguhr catalyst is prepared. i 1- example by making aslurry of kieselguhr and-a half molar solution of copper nitrate. takenin proportions such that the prepared reduced catalyst contains-20% byweight of copper. To this A copper on titania catalyst is prepared byfirst producing a titania gel by adding ammonia liquor to a solution oftitanium tetrachloride con taining 43 'gms. oi' the anhydrous salt per100 mls., filtering the precipitate oil and washing free from chloride.The filter cake so obtained is then slurried in a molar solution oicopper nitrate employing proportions of each which will give a fullyreduced catalyst containing about 20% copper. The copper is thenprecipitated by adding a 12% solution of sodium carbonate at roomtemperature until precipitation is complete. The filtered product iswashed substantially free from nitrate, dried and calcined at 400 C. forabout 4 hours. The catalyst is activated by reduction with hydrogen atabout 800 C.

When the process is operated continuously it is preferred to feed thedihydropyran and water. for example as an emulsion, to a preheater inorder to bring them to the reaction temperature and then to introducethem into the reaction zone. Preferably also the converter is packedwith catalyst on the spaced bed principle, that is with alternate layersof catalyst and an inert material serving to dissipate heat, for examplesilica chips or fish spine beads.

The invention is illustrated but not limited by the following examplesin which the parts are by weight unless otherwise stated.

Example 1 400 gins. or dihydropyran, 100 gms. or water and 40 gms. ofgranular ioraminate copper catalyst were charged to a 1 litre autoclavecomprising a chrome steel tube which could be heated electrically. Theautoclave was sealed and purged from air by means of nitrogen, andhydrogen was introduced at room temperature until the pressure was 100atmospheres gauge. The heaters were then switched on and the temperaturewas raised to 200 C. and the pressure to about 200 atmospheres gauge.Absorption of hydrogen commenced markedly at about 200 C. and thepressure was then allowed to fall to 150 atmospheres gauge. The reactionwas continued at a temperature of 200 C. and a pressure of 225-250atmospheres gauge for about 6 hours. when absorption of hydrogen ceased.The autoclave was cooled and discharged, and the product was freed fromcatalyst and distilled; There was obtained a yield oi 1,5-pentanediolamounting to about 90% of theoretical.

Example 2 400 gms. of dihydropyran, 100 gms. of water and 40 gms.otcopper barium chromite catalyst were charged to the autoclave describedin Example l and the process was carried out in the same way employingsimilar temperatures and pressures. Absorption of hydrogen ceased after6 hours. On distillation oi the filtered product there was obtained ayield of 1,5-pentanediol amounting to about 80% of theoretical.

Example 3 400 gms. of dihydropyran, 100 gms. of water and 40 gms.oractivated Raney copper powder 4 peratures and pressures were employed.Alter operating for 8 hours at temperature the absorptlon or hydrogenhad ceased.= On distillation or the iiltered product there was obtaineda yield oi Lli-pentanediol amounting to about 85% of theoretical.

Example 4 An emulsion comprising 4 parts of dihydropyran dispersed in 1part of water by weight by means 01 Turkey-red oil was led continuouslyto apreheater under a pressure or 250 atmospheres gauge oi hydrogen andthence to a packed converter at 200 C. at a liquid space velocity 0! 0.3hours-- of dihydropyran. The converter. which was 10' long x 2"diameter, was of chrome steel and electrically heated, and was packedwith W foraminate copper granules, there being alternate beds oicatalyst and silica chips of which the total volumes were 4 litres and 2litres respectively. The exit gas rate was 5 cu. metres per hour. 0ndistillation of the product 1,5-pentanediol was obtained in yield.

We claim:

1. A process for the production or 1.5-pentanediol which comprisesreacting 2,3-dihydropyran in the liquid phase with water and hydrogenunder at least50 atmospheres gauge and a temperature of at least 200 C.in the presence oi a copper containing hydrogenating catalyst. I

2. A process for the production 01 1.5-pentanediol which comprisesreacting 2,8-dihydropyran in the liquid phase with water and hydrogen ata temperature oi 250 to 275 C. and under a pressure of from 230 to 250atmospheres gauge in the presence oi a copper containing hydrogenatingcatalyst.

3. A process for the production oi 1,5-pentanediol which comprisesreacting 2,3-dihydropyran in the liquid phase with water and hydrogen atelevated temperature and pressure in the presence of a copper containinghydrogenating catalyst.

4. A process for the production of 1,5-pentanediol which comprisesreacting 2,3-dihydropyran in the liquid phase with water and hydrogen atelevated temperature and pressure in the presence or a copper bariumchromate hydrogenating catalyst.

5. A process for the production or 1,5-pentanediol which comprisescontinuously reacting dihydropyran in the liquid phme with water andhydrogen at elevated temperature and pressure in the presence oi acopper containing hydrogenating catalyst.

6. A process i'orthe production of 1,5-pentanediol which comprisescontinuously preheating dihydropyran and water, continuously feedingthem together with hydrogen to a reaction zone containing a coppercontaining hydrogenating catalyst and there reacting them under elevatedtemperature and pressure.

7. A process for the production of 1,5-pentanediol which comprisescontinuously preheating dihydropyran and water in the presence 0!hydrogen under elevated temperature and pressure and continuouslyfeeding them to a reaction zone containing a copper containinghydrogenating catalyst and there reacting them in the presence 01'hydrogen under elevated temperature and pressure.

8. A process for the production of 1.5-pentanediol which comprisescontinuously reacting 2,3-

were charged to the autoclave described in Examdihydropyran in theliquid phase with water and pie 1, and the same procedure and similartem-' 7 hydrogen at elevated temperature and pressure.

5 in the presence of a foraminate copperaluminium catalyst.

9. The process for the production of 1,5-pentanediol which comprisesreacting 2,3-dinvdropyran in aqueous emulsion with water and hy- 5drogen under a pressure of at least 30 atmospheres gauge and atemperature of at least 200 C. in the presence of a copper containinghydrogenating catalyst.

10. The process for the production of 1,5-pentanediol which comprisesreacting 2,3-dihydropyran in aqueous emulsion containing an emulsifyingagent with water and hydrogen under a REFERENCES CITED The followingreferences are of record in the file. of this patent:

UNITED STATES PATENTS Name Date Leuck et a1. Nov. 2, 1937 Number

